Round balers are well known, designed to form agricultural crops into cylindrical packages. All such balers include some type of mechanism for wrapping the formed bales with a wrap material including netwrap, which is a sheet material typically in the form of light, very thin web material, or twine, that is a filament. Round balers generally fall into two categories: fixed chamber balers or variable chamber balers. The fixed chamber balers generally include rollers or short sections of flat belts in fixed locations to define the bale chamber. This configuration provides many optional entry points for the wrapping material, provided at any transition between the rollers or belts.
The variable chamber balers typically include flat belts that form a variable size bale-forming chamber, and the entry point for the wrapping material is generally limited to the in-feed area or throat. FIG. 1 is a schematic of a typical variable chamber baler 100, as disclosed in commonly assigned U.S. Ser. No. 10/719,460, Filed: Nov. 21, 2003 entitled NETWRAP FEED AND CUT MECHANISM herein incorporated by reference, connected to a towing vehicle, such as a tractor 10. The tractor 10 includes an operator station 12 where information related to the performance of the baler is typically communicated to an operator, with controller 14, which includes a display and audio alarm. In operation, the tractor 10 tows the baler across the ground to feed the crop material 5 to throat 150 defined by a bottom belt roller 110, and an upper roller 120; both supporting the bale forming belts 130. The throat 150 typically also includes other rollers such as a starting roller 140 and drum roller 145 that assist in moving the crop material. Many configurations are known, but each includes what can be defined as an entry side 152 and an exit side 154. The entry side 152 is to be defined by the travel direction of the bale forming belts and crop material 5. For instance in the example illustrated in FIG. 1, the bale forming belts 130 are illustrated to travel in a direction that the outer circumference of the forming bale will move in a counter-clockwise direction. The crop material 5 will enter the throat 150 and be moved toward the bottom belt roller 110 at the entry side 152 of the throat. Balers have been designed to rotate the forming bale in the opposite direction, in which case the entry side of the throat would be defined by the upper roller 120.
The exit side 154 of the throat is defined by the upper roller 120, the point at which the bale forming belts 130 leave contact with the outer circumference of the forming bale. Most variable chamber balers operate so that the bale rotates in this manner, and due to the configuration of the supporting frame, a twine mechanism 160 is typically located near the exit side of the throat as shown. The twine 182 is fed from a supply roll 180 through the twine mechanism 160, such that the loose end of the twine is inserted to the nip point where the formed bale contacts the bottom belt roller 110 or, in this case, drum roller 145, from above any incoming material 5. An alternative configuration example is shown in U.S. Pat. No. 4,502,646, by Meiers. In both cases, the twine will begin restraining the crop material in the throat area as soon as it begins to feed, and any material fed into the baler, after the twine has started to wrap the bale, will be located on top of the twine, and will not be restrained by the twine. Thus, the typical method of operation of the baler has required the operator to stop the forward travel of the tractor and baler, to discontinue feeding material into the baler, before the twine mechanism starts to apply twine to the bale. At times this operation was slightly modified by the operator, by continuing to feed material in to the baler during a portion of the wrap cycle as the loose end of the twine was initially inserted, to assist in restraining the twine to the formed bale. However if an excessive amount of hay were fed into the baler at the same time as the twine was being fed, the resulting amount of un-restrained hay would negatively affect the appearance of the resulting bale. Thus, the amount of time that both crop material and twine are fed is minimized, to reduce the amount of crop material on the outside of the twine.
A desirable bale will typically be wrapped with a significant amount of twine that was applied under significant tension. In order to produce a desirable bale, the twine mechanism will go through two basic movements:
1. wrap cycle initiation and
2. the wrap cycle.
The wrap cycle initiation consists of the first movement from a home position, where the twine tie mechanism is positioned to minimize contact with the incoming crop, to a start-feed position where the loose end is inserted to the nip point. The wrap cycle consists of the reverse motion where the twine tie mechanism moves slowly back to its home position. The twine tie actuators are typically simple mechanical components, not capable of operating at significantly different speeds. Thus, the wrap cycle initiation typically takes a significant amount of time.
The coordination of initiating feed of twine, with discontinuing feed of crop material will maximize productivity of the baling operation: i.e. if the feeding of crop material is stopped before the twine mechanism begins to operate, the baler will be rotating the bale for several seconds, during the wrap cycle initiation, with no incoming crop material and no twine feeding. Balers typically include a bale size sensor that provides a bale size signal that is transferred through wire harness 16 to controller 14. The controller 14 is also typically operatively connected to an actuator for the twine mechanism. When the bale has reached the desired size an alarm or signal is transmitted to the operator, indicating that the forward travel of the baler should be stopped, to stop feeding material into the baler, at the same time the twine tie actuator is energized to start the twine tie cycle. These events typically happen at the same time, or with some selectable time delay between the alarm and the start of the twine tie cycle. Selectable delays ranging from 0 to 5 seconds have been provided, to allow the operator to have time to stop the baler before the twine cycle starts, while minimizing the delay that would result if the operator were required to stop the baler and to initiate the twine tie cycle at the same time. The selectable time delay allows the operators to compensate for variations in ground speed, ground conditions, and tractor capability.
Netwrap mechanisms, for wrapping bales with netwrap material 190, have been developed to feed the wrapping material to either the entry side or the exit side of the throat. A netwrap mechanism 170 that feeds the wrapping material to the entry side is illustrated in FIG. 1. Other mechanisms are illustrated in H. D. Antsey et al. U.S. Pat. No. 4,697,402 and Van Zee U.S. Pat. No. 5,129,208 both of which are herein incorporated by reference, while a mechanism that feeds netwrap material 190 to the exit side of the throat is disclosed in Underhill U.S. Pat. No. 5,036,642.
In the arrangement that inserts the netwrap material 190 at the exit side, the inserted netwrap material 190 will cover any crop material 5 coming into the baler, as soon as it begins to feed onto the bale, similar to the function of the twine mechanism. In the arrangement that inserts the netwrap material 190 at the entry side, where the netting is inserted underneath any incoming crop material, the netting will not cover incoming material until the forming bale has made nearly a complete rotation, wherein the starting edge of the netwrap material 190 will move from the entry side of the throat, around the circumference of the bale, and back to the exit side of the throat, which can take between 3 and 10 seconds, depending on the bale size and speed of operation of the baler. With netwrap material 190 that covers the full length of the bale, the bale needs to rotate only one and one-half to two rotations to achieve acceptable coverage. Thus, the duration of the wrap cycle is very short.
Control systems for the netwrap function typically parallel that of the twine tie function, wherein there is a bale size sensor that provides a signal to the operator to stop the baler, while at the same time initiating the wrap cycle. With this control technique, crop material is not fed during any portion of the wrap cycle, including those portions where the mechanism is moving from the home position to a feed position, and where the wrap material is moving around the portion of the bale's circumference that does not affect the incoming crop material. The speed of the wrap cycle will affect the productivity of the baling operation, and can be evaluated by the amount of time that crop material is not being fed into the baler. There is an opportunity to improve baling productivity by providing a control system to minimize the time required to complete the bale wrapping process, by allowing crop material to feed during a portion of the wrap cycle.
There is a need, therefore, for a more efficient process for bale-wrapping wherein crop material may be fed into the bale during at least some of the bale-wrapping cycle without compromising the integrity of the resulting bale.